How Do I Build Up Tough Clay Garden Soil?

“I live in the San Fernando Valley – Woodland Hills alongside the 101 freeway which follows the Los Angeles River. The soil is horrible – topsoil atop the riverbed, which was diverted to a cement-based flow.  How do I build it up – besides gypsum – are there plants more suited to help break it up long term.” Lorraine of West Hills, California

Answer: Your soil sounds very hardpan and tough. Upon research, I found this quote: “Soil in Woodland Hills tends to be hard, compact clay…the curse of most Valley gardeners” -Melinkoff, 1987. Thankfully, there are measures that you can take to add fertility to your soil and loosen it up a bit for easier gardening.

The trouble with clayey soils is that they lack aeration, good drainage, and become very hard when dry. This disables water percolation and the fine roots of plants from gathering necessary air and moisture for top performance. Here are several measures that I would take to improve soil performance.

Add Organic Matter

For organic amendments to be effective in clay soils, they need to be evenly incorporated in quantity. Add amendments, like compost, peat moss, earthworm castings, and composted manure, into your soil at a ratio of two parts amendment to one part ground soil. Till them in or work them in with a turning fork when your clay soil is damp. Make sure they are well incorporated. The deeper you amend, the more you will improve bed performance. You might also consider berming your soils to lift them above the soil level. (Click here to learn more about berming.) Organic amendments should be added yearly to maintain good fertility.

In more arid regions like yours, the application of mulch will reduce wind erosion and hold moisture at plant root zones. (Click here for an overview of the best garden mulches and decorative covers.)

Add Mineral Components

Adding mineral components, like gypsum, can also increase the porosity and improve the structure of clay soils. A hefty application of gypsum will certainly help improve soils heavy in clay. Other minerals, like granite dust, greensand, and lime, may also be helpful in this manner. Mineral components should be applied along with organic matter for a better long-term solution to loosening and improving clay soils.

Add Topsoil

True topsoil generally contains a generous amount of loamy mineral soil with better porosity and fertility than yours because loams contain even parts sand, silt, and clay. Mix it into your beds at a 1:1 ratio, being sure to incorporate the two soils well. If you incorporate topsoil into your beds, as well as regular organic matter, you will be set!

Choose Raised Beds

Finally, you can build your beds upwards. Raised beds are an excellent choice for gardeners living in areas with poor soils. I recommend that you watch the video below that details raised bed pros and cons.

I hope that these tips help.

Happy gardening,

Jessie Keith


How Do I Calculate Compost Application Rates?

“How do I calculate compost application rates to yards?  I am trying to figure how much to order.” Question from Anne of Elmdale, Kansas 

Answer: To determine how much compost, topsoil, or mulch to apply to beds, use the formula below along with a conversion table and links to other helpful sources–most notably, a great article for easily calculating the square footage of beds of various shapes.

Amendment Application Formula for Beds

For square or rectangular beds, multiply the bed’s length by its width to get square footage (L *W= ft2). If you wish to lay mulch 2-inches deep, then have a look at the table below to get the corresponding square footage covered by 1 cubic yard of compost, mulch, or peat moss. Then divide the square footage in the table that matches the 2-inch depth.

For example: If you had a 12-foot x 24-foot bed that required 2 inches of peat moss for tillage, calculate 12 feet x 24 feet = 288 square feet, then from the chart you can determine that 288 ft2/162 ft = 1.78 cubic yards of mulch. 

Square Feet to Cubic Yards Conversion Table

1 cubic yard of an amendment or mulch will cover the following square footage to each depth.

Depth of Amendment

Square Footage Covered


324 ft2


162 ft2


108 ft2


81 ft2

To calculate the square footage of other bed shapes, please click here for an excellent reference. You can also click here to view a handy mulch/amendment calculator.

Spring is the best time to liberally apply compost or mulch to gardens, but if you also plan to do significant fall planting, reapply in autumn. Organic matter breaks down over the course of the season and needs to be replenished. If you plan any winter or cold-frame gardening, apply compost as both an amendment and protective mulch.

Happy gardening,

Jessie Keith

Black Gold Horticulturist

Why Does My Amended Container Soil Become Compacted?

Why Does My Amended Container Soil Become Compacted?

“Why does the soil in my container garden compact super tight? I use garden soil mixed with potting mix and perlite.” Question from Nell of Salem, Indiana

Answer: It sounds like your soil ratios are off, and your in-ground soil is high in clay. If you have not added the right amount of Black Gold amendment or potting soil to clay-rich ground soil, then compaction can be a problem. This is because clay-rich soil has very small particles and becomes compacted very easily. When you add organic matter, such as the peat moss and aged bark found in our potting soil, it lifts the soil, making it more porous and aerated, while allowing it to hold water better. Mineral ingredients, like perlite, also increase aeration and drainage.

You have two options. Either fill your containers with nothing but potting mix–we recommend either Black Gold Natural & Organic Potting Mix or Black Gold Natural & Organic Raised Bed & Potting Mix–or mix your ground soil with more organic amendments. We would recommend adding a 1:3 ratio of ground soil to Black Gold Garden Compost Blend with added Black Gold Perlite to maintain porosity. (Click here for more tips for amending clay-rich soil and click here to learn more about succeeding with container gardening.)

Happy gardening,

Jessie Keith

Black Gold Horticulturist

How Do I Organically Feed My Vegetable Garden Soil for Fall?

How Do I Organically Feed My Vegetable Garden Soil for Fall?

“I’m getting ready to prep my raised beds for the fall crop.  What is best to amend the soil with since I do not use chemical fertilizers?” Question from Randal of Chiply, Florida.

Answer: There are lots of things that you can do to feed your soil for fall and winter crops. Here are some of easy options.

Feed Your Soil

Your garden is as good as its soil. For success, liberally feed it with organic matter, such as Black Gold Earthworm Castings, Canadian Sphagnum Peat Moss, and Garden Compost Blend, especially if your soil is rich in clay or sandy. Add at least 3 inches of the amendment to the soil surface, and till it to a depth of at least 8 inches. Tilling in amendments will increase water-holding capacity and aeration for better root growth. Use the amendment application formula below to determine the amount you will need.

Amendment Application Formula

([area to cover] ft2 x [depth in inches desired] x 0.0031 = ___ yd3).

Example: If you wanted to cover a 20 square foot area with 2 inches of compost, the result would be: 20 ft2 x 2 inches of compost x 0.0031 = 2.48 yd3.

(Click here for a full overview of how to prep a new vegetable garden from start to finish.)

Choose the Right Organic Fertilizer

Vegetables perform better with regular fertilization, especially heavy feeders like tomatoes. In fact, most veggies will deplete the soil of nutrients over time, so replenishment is necessary. There are many organic vegetable fertilizers on the market. Alfalfa, blood, bone, feather, fish, kelp, and shrimp meals are all common natural components of non-chemical fertilizers. Earthworm castings are also a good source of nitrogen and beneficial microbes. Adding mycorrhizae to the soil is also useful because it helps plants take up water and nutrients better. Black Gold Natural & Organic Ultra Coir is another of our organic-rich amendments that also contains our proprietary blend of endomycorrhizae. We recommend that you research top-rated organic fertilizers to find the best for your needs.

Rotate Your Crops with Legumes

Vegetables, especially tomatoes, should be rotated on a three-year cycle–tomato one year and other vegetables the next two years. Legumes, like beans and peas, are excellent rotation crops because they naturally fortify soils with nitrogen. For more rotation tips, I encourage you to read Spring to Fall Vegetable Rotation: Planting for Non-stop Garden Produce. It will provide all of the information you need to effectively rotate your crops, whether container- or garden-grown.

I hope that all of this information helps! We have many more articles about gardening in Florida, click here to view them.

Happy fall vegetable gardening,

Jessie Keith

Black Gold Horticulturist

What Is The Best Soil for Raised Beds?

“I built 2 beds measuring 4′ x 16′ and 2 foot deep.  I don’t think I need a Black Gold mix for the bottom half.  What is something I could [add to] the bottom half of the boxes?  Also are Black Gold products meant as a supplement to the soil or a soil replacement?” Question from Kevin of Rome, Georgia

Answer: We have many amendments and soils suitable for raised bed gardening, but we now sell a natural raised bed soil that is specially formulated for your type of garden. Black Gold® Natural & Organic Raised Bed & Potting Mix is just for raised bed gardening, is sold in cost-effective large bales and is OMRI Listed for organic gardening. If you wish to supplement with additional soils or amendments, try the following bulk and/or bagged options.

  1. Quality screened bulk compost, leaf compost, or mushroom compost – These are all rich and fortifying but high in organic matter, which eventually breaks down over time and needs to be replenished.
  2. Quality screened bulk topsoil – Topsoil contains mineral soil as well as organic matter, so not all of its components will break down over time.
  3. Bagged compost, such as Black Gold Garden Compost Blend – This is a good option for smaller-scale raised bed gardening. Treat it as you would bulk compost.

Products sold in bulk are generally available at large landscape supply centers and are sold by the yard. Add topsoil of compost at a ratio of one part topsoil or compost to two parts bagged mix.

Before ordering any soil, be sure you know how much you need by using the soil application formula. Also, be sure to feed your soil with quality fertilizer formulated for vegetable gardening.

Soil Application Formula

To find the amount of soil you will need, determine the volume of your square or rectangular bed by measuring its length, width, and height. Then use the following formula: V = L x W x H.

V = soil volume
L = bed length
W = bed width
H = bed height

So, if your bed happens to be 6 feet x 4 feet x 1.5 feet, multiply 6 x 4 x 1.5 = 36 cubic feet. Our raised bed soil is sold in 2.2 cf bales. To determine the amount of bagged soil you might need (36 cubic feet/2.2 cf bales= 16). If you plan to add topsoil at a 1:3 ratio, then you will need 2/3 mix (24 cubic feet (10.66 2.2 cubic foot bags of raised bed potting mix)) and 1/3 topsoil (12 cubic feet of topsoil). If you want to buy topsoil by the yard, then you must know yardage. Divide the answer in cubic feet by 27 to get the number of cubic yards you might need (36/27= 1.3 cubic yards).

Happy gardening,

Jessie Keith

Black Gold Horticulturist


(For more tips click here for a full overview of how to prep a new vegetable garden from start to finish.)

I hope that these tips help.

Happy gardening,

Jessie Keith

Black Gold Horticulturist

Black Gold® Perlite

We process premium Black Gold® Perlite for horticultural use, so it can be used and enjoyed by the everyday gardener. Use it as a potting soil amendment to increase the porosity and drainage of mixes, or use it alone to propagate plant cuttings. Black Gold® Perlite is also OMRI Listed® for organic gardening, so amend your favorite potting mixes with confidence.

Click here for an informational pdf.

How Do I Calculate How Much Peat to Add to My Garden?

“I purchased 3.0 CF bags of Black Gold Peat Moss. What is the expanded volume of this bag? I need 3.5 cubic yards of peat for my raised bed garden mix, so was going to buy 32 of these bales…but realized it’s going to expand. How do I calculate how much to buy?” Question from Dave of Utah

Answer: To determine the expansion of 3.0 cubic foot bales of Black Gold Peat Moss anticipate it at a 2:1 ratio. So, the bales should expand to 6 cubic feet when properly fluffed. One cubic yard equals 27 cubic feet, so to determine the amount you need in cubic yards calculate 3.5  x 27 = 94.5. Then divide 94.5 by 6 for a total of 15.75 bales. I’d go with 16 bales of peat to be safe.

I hope that this helps!


Jessie Keith

Double Digging for Flawless Root Crops

Root crops such as ‘Lunar White’ carrots will be long, straight, and easy to pull when grown in your newly double dug beds.

Root crops grow best in soil that is as fertile and deep as possible. Higher soil organic matter and tilth will yield longer, straighter carrots, heftier rutabagas and prettier parsnips. Double digging is the best technique to maximize bed depth, and early spring or midsummer are great times to prep your beds for spring or fall root crops.

The best way to maximize soil depth and quality is through double digging and ample amendment with lots of organic matter. Double digging is the process of digging deeply to ensure soil is light and porous down deep. Begin by designating a reasonable area to dig. Then with a good, sharp spade, remove the top 8 to 10 inches of soil and place it on a tarp so it can be easily returned to the garden. For the “double” stage of digging, use a hefty garden fork to work up the soil as deeply as possible along the floor of the garden where the soil was removed.

Double Digging - 3 Steps - Jessie Keith
1) Trench double digging is a faster, less arduous method of double digging. Just double dig a trench where you want to plant. 2) All double-dug soil should be friable, clump-free and amendments thoroughly worked in. 3) Double dug bed spaces will be slightly raised upon completion and should be easy to dig deeply into.

Once light and worked up, add a half and half mix of Black Gold Garden Soil and Black Gold Garden Compost Blend—one bag each for around a 5’ x 5’ garden area. Finally, work in additional bags of soil builder and compost at the same ratio into the soil on the tarp and add it back into your double dug garden.

This method is a lot of work but yields superb root vegetables for years to come. Follow up by planting rows of your favorite fall root crops, like carrots, daikon radishes, rutabagas, beets, and parsnips, and cover the seed lightly with Black Gold Seedling Mix before watering in.

Enjoying Root Vegetables - Jessie Keith
1) Kids enjoy helping harvest root vegetables and eat them too. 2) Long, straight ‘Kinko’ Carrots harvested directly from the fall garden.

Soil, Seed and Supplies: Planning Your Garden

The Three S’s of Garden Planning boils down to: soil, seed and supplies.

One of the best things about backyard food gardening is that it demands we live by the seasons. Spring is for planning your garden. Summer demands maintenance. Autumn is the harvest. Most important of all is winter – the time for planning. Just as a landscape architect creates a garden on paper before it’s bid or built, it saves a lot of money and time to use January to plan your own food garden with research, notes and sketches. Do it right and you control your costs. You’ll save time to when plants and supplies will be on hand when you need them.


Planning Your 2012 Garden - Soil

Soil improvement is the most important part of organic gardening. For existing gardens, plan to add amendments and fertilizers to your soil every year to compensate for what last year’s garden drew out. Amendments should be thoroughly tilled in to feed microbes so their numbers do not decline. Some of the best choices are: Garden Compost Blend, Earthworm Castings, and Just Coir for more water retentive soils in dry climates.


Research vegetables for your garden via online or print catalogs. Measure the garden and sketch out a basic boundary to help you remember what you grew last year and where you’ll grow each new plant. This allows you to rotate your crops so that each square foot grows an entirely different kind of plant each year. It is well known that diseases build up to big problems when plants inhabit the same place year after year.

Planning Your 2012 Garden - Seed Catalogues

Gather sticky tabs, a yellow highlighter and a note pad before starting in on your seed catalogs. Your ability to mark interesting varieties and take notes is a big help since there are so many kinds of lettuce, peppers and squash to choose from. Ordering online is a lot easier because you won’t have to write out all those seed names on a form. Click and buy makes growing from seed fast and easy.


Order supplies you’ll need for growing from seed so they’re on hand when it’s time to start. Black Gold Seedling Mix offers the perfect sterile medium to germinate seed successfully in a flat topped with clear plastic cover to retain warmth and heat. When the seedlings put on their second leaves you’ll need to move them into individual small pots with more fertile Black Gold Natural and Organic Potting Soil to mature further until they are large enough to move outside. When it’s time to plant them into the garden you’ll need starter & transplant fertilizer to help them quickly adapt to their new summer home.